Bearing analysis please

[toomanymodz]

Less than 500 miles on this new and very expensive engine. Oil pressure was barely 10 psi hot idle, even when first fired it had low pressure. Engine originally had chevy-style solid roller lifters in it, and I observed the valley filling up with oil. I've since switched to Morel solid roller lifters and the oil getting upstairs looks normal, but I think the pan may have been sucked dry. Look at these main bearings. What do you see? (the pink line is plastigauge.. 003 clearance).

A close-up.

 

[Reggie West]

Was this a TA aluminum block?

 

[toomanymodz]

Was this a TA aluminum block?

Yes it is. And .003 is loose in my opinion. Main bearing expansion is huge with aluminum blocks.

 

[Nick Micale]

Yes it is. And .003 is loose in my opinion. Main bearing expansion is huge with aluminum blocks.

I agree.

We have done more TA alum block builds than anyone, from the first pro-type block, to 4 alum builds now in process, and one that shipped Friday, so maybe a conversation would be in order?

My alum block has over 1000 passes and has never had any main bearing issues, and is usually freshened after 200-250 passes.

Oil pressure is 90-100 PSI on start up, 50 PSI at idle, 35 PSI after a 9 sec. pass, back to 50 PSI when returning to the pit area.

 

[bison]

Yes it is. And .003 is loose in my opinion. Main bearing expansion is huge with aluminum blocks.

.003"? At ambient temps. What is it at 200* .004? Maybe a little more

 

[Reggie West]

Crane makes a special lifter for that block that will allow more oil to flow back to the block. I believe they call it a shielded lifter.

When you said you saw a lot of oil in the valley that gave it away.

When people first started using those blocks, you could be at 0 oil pressure at the end of a run, not good.

I am sure Nick can give you all the info on it as well as Jeff Rand.

I will try to run down the part number on the lifters. Was anything else hurt?

 

[RanRanBoBandy]

I agree.

We have done more TA alum block builds than anyone, from the first pro-type block, to 4 alum builds now in process, and one that shipped Friday, so maybe a conversation would be in order?

My alum block has over 1000 passes and has never had any main bearing issues, and is usually freshened after 200-250 passes.

Oil pressure is 90-100 PSI on start up, 50 PSI at idle, 35 PSI after a 9 sec. pass, back to 50 PSI when returning to the pit area.

Nick, what do you recommend for main clearance on a TA alum block for street and strip?
Thanks.

 

[nat86]

I agree.

We have done more TA alum block builds than anyone, from the first pro-type block, to 4 alum builds now in process, and one that shipped Friday, so maybe a conversation would be in order?

My alum block has over 1000 passes and has never had any main bearing issues, and is usually freshened after 200-250 passes.

Oil pressure is 90-100 PSI on start up, 50 PSI at idle, 35 PSI after a 9 sec. pass, back to 50 PSI when returning to the pit area.

And I'm looking forward to getting that engine this Friday [emoji6]

Sent from my SM-N910T using Tapatalk

 

[No disintegrations]

Less than 500 miles on this new and very expensive engine. Oil pressure was barely 10 psi hot idle, even when first fired it had low pressure. Engine originally had chevy-style solid roller lifters in it, and I observed the valley filling up with oil. I've since switched to Morel solid roller lifters and the oil getting upstairs looks normal, but I think the pan may have been sucked dry. Look at these main bearings. What do you see? (the pink line is plastigauge.. 003 clearance).

View attachment 278335

A close-up.
View attachment 278336

I don't think the plastigauge after the fact is telling much because of too much damage to the bearing.

 

[toomanymodz]

I'll continue tearing it down this week. Thus far the crank itself looks good. The rod bearings appear to have filet ride occurring because they're down to the copper on the edges. I had performed a leak-down a few weeks ago and it had 9%, with the worst cylinder at 16% and best at 4%, so I'm not thrilled about that either.

 

[Boost231]

Sad. I don't want to ask how much you spent on building it

Sent from my SM-N910T using Tapatalk

 

[bison]

I'll continue tearing it down this week. Thus far the crank itself looks good. The rod bearings appear to have filet ride occurring because they're down to the copper on the edges. I had performed a leak-down a few weeks ago and it had 9%, with the worst cylinder at 16% and best at 4%, so I'm not thrilled about that either.

What crank?

 

[toomanymodz]

Thank goodness it's a billet crank. I think that's what saved the journals, for they look almost unblemished. I think I'll install new rod and main bearings and give it a go. I've since installed Morel solid roller lifters and they don't hemorrhage oil in the valley like the chevy lifters did. With such limited free time, it'll take me a few months before it's running again. Summer is almost here and it rains every day, so I won't feel quite so bad since it's raining anyway.

 

[Reggie West]

The problem is you are not hemorrhaging enough. The lifters do not allow enough oil to drain back through the valley of the block.

Nick I don't have the part number for those lifters. Do you?

 

[Nick Micale]

The problem is you are not hemorrhaging enough. The lifters do not allow enough oil to drain back through the valley of the block.

Nick I don't have the part number for those lifters. Do you?

Oil drain back in the alum block requires a few different operations than a stock block or stage block, and also depends of the build requirement for HP and RPM levels as well as solid or hydraulic lifters?

All our alum builds are done to the customer's specific requirements and the ultimate use.

 

[Chuck Leeper]

The rod bearings appear to have filet ride occurring because they're down to the copper on the edges.

So, no to very little rod side play on the build??

 

[Nick Micale]

So, no to very little rod side play on the build??

That indicates the rod bearings were not properly prepared before installation?

 

[Chuck Leeper]

That indicates the rod bearings were not properly prepared before installation?

My thots, exactly. Big difference in a rolled filet, and one ground when the crank is finished.
Lack of oil flow due to no side play, is doom for the brgs.....

 

[toomanymodz]

So, no to very little rod side play on the build??

It's near the minimum at .011 to .012. I've ran Chevrolet engines at this clearance.

 

[toomanymodz]

Update. All of the journals looked fine, so I installed 1 under main bearings to get the clearance in spec. They are now at .0018 - .0019 range. Time to put the pan back on. Not sure when I'll have time to put the engine back in. It's gonna be a busy next few months. Just glad I've got the bearing issue fixed.